To be clear, it doesn't support casting, which is what the previous commenter was asking for.
It runs directly on android tv. The app even says that there is no support for phones or tablets so casting isn't going to work.
I also agree that casting is the major missing feature from all these apps. Mirroring might be a substitute for some but, again to be clear, it isn't the same as casting and in most cases the quality is going to suffer significantly.